I recently developed a programmable phage display for identifying pathogenic antigens related to human paraneoplastic neurological disorders (PNDs). This workplace me in the rapidly emerging area of neuro- immunology, as PNDs are debilitating central nervous system disorders that involve autoimmune encephalitis. Patients with PND harbor autoantibodies against brain antigens, and specificity in the autoantibody profile predicts clinical symptoms and prognosis. I have characterized the largest set of antigens that are linked specifically to patient PNDs, one of which, KLHL11, was novel and published recently. In Aim 1, I will characterize the additional antigens and test my hypothesis that a single epitope is causal to PND patient autoimmunity and encephalitis. The K99 will allow me to acquire the advanced bioinformatics skills necessary for epitope analysis, strengths of the mentor's lab. In Aim 2, I test whether intracellular PND antigens cause autoimmune encephalitis through a non-canonical MHC-I class-dependent pathway, an unexpected mechanism with implications for treatment. I will create a new mouse model for anti-KLHL11 PND and a complementary KLHL11 knockout mouse. Together with existing mice deleted in immunity genes, I will use immunohistochemistry (IHC) and single cell sequencing to test dependence in specific targeting of T-cells in the brain of PND on the non-canonical MHC pathway. The K99 will allow me, with classes and advisors, to acquire the necessary advanced knowledge in immunology built into Aims 2 and 3 and help guide the initial T cell studies. Further, the UCSF mission, including infrastructure and research environment, is geared particularly towards facilitating direct interactions between basic and clinical immunologists and neurologists. I plan to continue to exploit this specialized environment as I transition to the R00 phase in this aim. In Aim 3, I bring to bear my previous expertise in mouse genetics and cellular neurobiology, and my K99 acquired molecular immunology expertise, to leverage PND antigens (Aims 1 and 2) to generate 3D anatomical maps of targeted inflammation in the brain. I will test whether brain region-specific PND encephalitis is mediated by the CNS lymphatic system. IHC with brain clearing for T cells, at different times after initiation of PND, will provide a comprehensive ?3D? roadmap of the invading T cells and their relationship to antigen-expressing cells. My proposed studies will result in a comprehensive picture of the mechanisms determining how neuronal antigens elicit a brain autoimmune response, and assuming T cell migration routes are specific for anatomically distinct auto immunities, pave the way for identifying neuronal circuitries underlying the distinct PND pathologies, my goal as an independent investigator.